Add Solana support to Across swapper and update contracts

[0xh3rman]

Bring back #670

[semanticdiff-com]

Review changes with  

Changed Files

File	Status
crates/gem_evm/src/across/contracts/spoke_pool.rs	45% smaller
crates/gem_evm/src/across/deployment.rs	15% smaller
crates/swapper/src/across/provider.rs	13% smaller
crates/gem_solana/src/jsonrpc.rs	1% smaller
Cargo.lock	Unsupported file format
crates/gem_evm/src/chainlink/contract.rs	0% smaller
crates/swapper/Cargo.toml	Unsupported file format
crates/swapper/src/across/mod.rs	0% smaller
crates/swapper/src/across/models.rs	0% smaller
crates/swapper/src/across/solana.rs	0% smaller
crates/swapper/src/chainlink.rs	0% smaller

[gemini-code-assist]

Summary of Changes

Hello @0xh3rman, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly expands the capabilities of the Across swapper by integrating Solana blockchain support. The changes involve updating core contract interfaces to a more generic V3 standard, introducing Solana-specific data handling for addresses and transaction messages, and adapting gas estimation mechanisms to accommodate Solana's fee model. This allows for seamless cross-chain asset transfers where Solana can act as a destination chain.

Highlights

• Solana Integration: Introduced comprehensive support for Solana blockchain within the Across swapper, enabling cross-chain swaps to and from Solana.
• Across V3 Contract Updates: Updated the Across SpokePool contract interface to V3, changing address types from address to bytes32 for broader compatibility across different blockchain ecosystems, including Solana.
• Solana-Specific Logic: Implemented new modules and functions to handle Solana-specific address encoding (bs58 to bytes32), transaction message construction, and gas estimation using Solana's getRecentPrioritizationFees.
• Dependency and Configuration: Added the borsh serialization library for Solana data structures and updated AcrossDeployment to include Solana chain type and its unique chain ID and asset mappings.

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[gemini-code-assist]

Code Review

This pull request introduces Solana support to the Across swapper, which is a significant and welcome enhancement. The refactoring to support non-EVM chains is well-structured, particularly the introduction of QuoteContext and RelayRecipient which improves code clarity. However, I've identified several critical issues in the fee calculation logic for Solana swaps that could lead to incorrect quotes. There are also a few medium-severity concerns regarding potential data conversion overflows and indexing that should be addressed to ensure robustness.

[gemini-code-assist]

The conversion from U256 to u64 for fee_amount and user_amount could lead to an overflow if the token amount is large, especially for tokens with a high number of decimals (e.g., 18). While this is safe for USDC (6 decimals), it would be more robust to handle this potential overflow explicitly, perhaps by checking the amount against u64::MAX before the conversion. This is a limitation of the underlying Solana transfer_checked instruction, but adding a safeguard here would make the code more robust for future tokens.

[gemini-code-assist]

The account indices are being generated as 1-based (idx + 1), but Solana's CompiledInstruction format typically uses 0-based indices. This is likely to cause transaction failures on-chain unless the Across handler program specifically expects 1-based indexing. It's recommended to use 0-based indexing to align with standard Solana conventions.

Suggested change

	account_index_map.insert(account.to_base58(), (idx + 1) as u8);
	account_index_map.insert(account.to_base58(), idx as u8);